Novel 2-phenyl-thianaphthenediamidines



United States Patent 3,388,135 NOVEL Z PHENYL-THHANAPHTHENE- DHAMIDINES Otto Darin, Meiiwaldstrasse 11, Erlangen-Bubenreuth, Germany No Drawing. Continuation-impart of application Ser. No. 431,697, Feb. 10, 1965. This application June 15, 1967, Ser. No. 646,297 Claims priority, application Germany, Feb. 19, 1964,

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ABSTRACT OF THE DISCLOSURE The compounds are di-amidino-substituted 2-phenylthianaphthenes useful as trypanocides in warm-blooded animals.

This is a continuation-in-part of copending application Ser. No. 431,697, filed Feb. 10, 1965, now abandoned.

This invention relates to novel Z-phenyl-thianaphthenediamidines and acid addition salts thereof, as well as to methods of preparing these compounds.

More particularly, the present invention relates to 2- phenyl-thianaphthenediamidines of the formula METHOD A By reacting a 2-phenyl-thianaphthene-dinitrile of the formula CN Vs NC R2 (1D wherein R and R have the same meanings as in Formula I, with a hydrogen halide to form a di-hydrogen halide salt of a 2pheny1-thianaphthene-diiminoether of the formula I H-HN I m 0 lower alkyl lower alkyl 0 (III) wherein R and R have the same meanings as in Formula I and Hal is a halogen, and reacting the di-iminoether salt III with ammonia.

The conversion of the dinitrile II into the di-imino ether salt III and the latters reaction with ammonia are advantageously carried out in the presence of anhydrous solvent at room temperature. The employment of a dry "ice gaseous hydrogen halide is preferred to effect the conversion of the dinitrile into the di-iminoether salt, and dry gaseous ammonia is preferably used for conversion of the di-iminoether salt into the desired end product. Chloroform is preferred as the solvent medium.

The Z-phenyl-thianaphthene-dinitriles of the Formula II, which are used as starting compounds for the preparation of the novel diamidines according to this method, are themselves novel and may be prepared by methods involving well known chemical principles; for example, by subjecting a tolyl-methylphenacyl-sulfide to a ring closure reaction to form a 2-tolyl-methyl-thianaphthene, halogenating the two methyl groups, converting the halomethyl groups into aldehyde groups, converting the dialdehyde into the corresponding dioxime, and dehydrating the dioxime with a conventional dehydrating agent.

For instance, m-tolyl (4 methyl phenacyD-sulfide (M.P. 44-45" C.) is subjected to a ring closure reaction with aluminum chloride to form 2-(p-tolyl)-6-rnethy1- thianaphthene, which is then brominated with bromosuccinimide to give the corresponding 4,6-bis-brornoethyl compound (M.P. 19ll93 C.), the latter is then transformed with hexamethylenetetrarnine into 6-formyl- 2-(4'-formyl-phenyl)-thianaphthene, which is converted into the corresponding dioxime (M.P. 270-272 C.), which is in turn reacted with acetic acid anhydride to form 6-cyano-2-(4'-cyanophenyl)-thianaphthene (MP. 262-265 C.).

6-cyano 2 (3 cyano-phenyl)-thianaphthene (M.P. 217-218.5 C.) and 5-cyano-2-(3-cyano-phenyl)-thianaphthene (M.P. l-191 C.) may be prepared in analogous fashion. However, these two starting compounds may be more conveniently prepared from the more readily accessible mor p-tolyl-3 brorno-phenacyl-sulfidc through the intermediate 6- or 5-formyl-2-(3'-brotnophenyl)-thianaphthene, conversion of the latter into the corresponding mono-oxime which is treated with a dehydrating agent to form 6-cyano-2-(3'-bromophenyl)- thianaphthene (MP. l58-159.5 C.) or 5-cyano-2-(3'- bromophenyl)-thianaphthene (MP. 165-166 C.), and subsequent replacement of the bromo-substituent by the cyano group pursuant to conventional methods.

METHOD B By heating a mixture of a dicyano-substituted Z-phenylthianaphthene of the Formula II with ammonium thiocyanate to a temperature of to 250 C. in the absence of a solvent.

The Z-phenyl-thianaphthene-diamidines I obtained by the above-described methods of preparation are organic bases and may, if desired, be converted into their nontoxic, pharmacologically acceptable acid addition salts by known methods, such as by dissolving the free base in water and acidifying the aqueous solution with one or more two molar equivalents of the desired inorganic or organic acid. Examples of inorganic and organic acids which form non-toxic, pharmacologicolly acceptable acid addition salts with the 2-phenyl thianaphthene-diamidines according to the present invention include, but are not limited to, hydrochloric acid, sulfuric acid, phosphoric acid, tartaric acid, citric acid, succinic acid, maleic acid, 8-chlorotheophylline and the like.

The following examples further illustrate the present invention and will enable others skilled in the art to understand the invention more completely. It should be understood, however, that the invention is not limited to the particular examples given below.

Example 1.Preparation of 6-amidino-2-(4'-amidinophenyl)-thianaphthene dihydrochloride by Method A 6 gm. (0.023 mol) of 6-cyano-2-(4-cyano-phenyl)- thianaphthene were dissolved in 500 cc. of chloroform,

the resulting solution was filtered, and the filtrate was admixed with 50 cc. of absolute ethanol. Thereafter, while cooling exteriorly with ice, the ethanolic solution was saturated with gaseous hydrogen chloride which had been dried by passing it through concentrated sulfuric acid. The reaction solution Was then allowed to stand for two days at room temperature, and thereafter dry gaseous hydrogen chloride was again passed through it for one hour. The reaction solution Was then allowed to stand at room temperature for five days, and at the end of that time the crystalline substance which had separated was isolated by vacuum filtration and dried. 6 gm. (65% of theory) of the di-iminoether dihydrochloride of the formula HCLHN NILHCI were obtained.

700 cc. of absolute ethanol were saturated with dry gaseous ammonia, and the resulting solution was admixed with the dry di-iminoether dihydrochloride previously obtained. A suspension was formed whose solid component went into solution after a short period of standing at room temperature. The solution was allowed to stand at room temperature for four additional days, and then the almost white precipitate formed during that time was separated by vacuum filtration. It was identified to be 6-amidino-2-(4'-amidino-phenyl)-thianaphthene of the formula HN NH 1 gm. of 6-cyano-2-(4'-cyano-phenyl)-thianaphthene was intimately admixed with 3 gm. of ammonium thiocyanate, and the mixture was heated for two and a half hours at 180 C. Thereafter, the reaction mixture Was admixed with dilute hydrochloric acid, the resulting solution was filtered, and the filtrate was admixed with acetone until formation of the precipitate caused thereby was complete. The precipitate was separated and was identified to be 6-amidino-2-(4-amidino-phenyl)-thianaphthene dihydrochlcride, M.P. 365-370 C., i.e. identical to the dihydrochloride obtained in Example 1.

Example 3.Preparation of 6-amidino-2-(3'-amidir1ophenyl)-thianaphthene by Method A Using a procedure analogous to that described in Example 1, 6-amidino-2-(3-amidino-pheny1)-thianaphthene of the formula NIT;

was prepared from 6-cyano-2-(3'-cyano-phenyl)-thianaphthcnc. Its dihydrochloride had a melting point of -200 C.

Example 4.Preparation of 5-amidino-2-(3'-amidinophcnyl)-thianaphthene by Method A Using a procedure analogous to that described in Example l, 5-amidino-2-(3amidinophenyl)-thianaphthene of the formula was prepared from 5-cyano-2-(3-cyano-phenyl)-thianaphthene.

The compounds of the present invention, that is, those embraced by Formula I and their non-toxic, pharmacologically acceptable acid addition salts, have useful pharmacodynamic properties. More partioularly, they exhibit highly effective trypanocidal properties in warmblooded animals, such as cattle, horses, antelopes, dogs and camels; in other words, they are destructive to trypanosomes, such as T rypanosoma gambiense and T rypanosoma rlzoderiense.

For pharmaceutical purposes the compounds of the present invention are administered subcutaneously to a warm-blooded animal infected with Trypanosoma, i.e., by subcutaneous injection of a sterile aqueous 1% solution of the active trypanocidal ingredient. Most preferably, the hypodermic solution is prepared immediately prior to administration from a sterile ampule containing 200 mgm. of the active ingredient. The average trypanocidally effective single dose of the compounds according to the present invention is 3 mgmj kg. body weight.

While the present invention has been illustrated with the aid of certain specific embodiments thereof, it will be readily apparent to others skilled in the art that the invention is not limited to these particular embodiments,

and that various changes and modifications may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A compound of the formula NH Fl 0 mg Nrn o H N References Cited UNITED STATES PATENTS 6/1940 Ewins et al. 260-564 3/1942 Ewins et al. 260564 JOHN D. RANDOLPH, Primary Examiner.

C. M. SHURKO, Assistant Examiner. 

